(Reuters) – Delaware on Thursday became the latest U.S. state to take action to extend marriage rights to gay and lesbian couples, as Governor Jack Markell announced a bill to legalize same-sex marriage.

Markell, a Democrat, said in a telephone interview that while he was confident the bill would pass, given that his party controls both the upper and lower chambers of the legislature, “nothing is sure until it’s done.”

“What we know is same-sex couples want to get married for the same reason that other couples want to get married,” Markell said in a telephone interview.

Markell announced the legislation at an afternoon press conference, where he was joined by state Senate President Pro Tempore Patricia Blevins, House Speaker Pete Schwartzkopf and Attorney General Beau Biden, Markell’s office said.

Three other states are considering bills on same-sex marriage, while nine states and the District of Columbia have already legalized gay marriage.

In 2011, Markell signed into law a bill authorizing civil unions for same-sex couples.

Republican state Senator Brian Pettyjohn said he believed Delaware’s civil union law, which was approved before he took office, went gone far enough and has been a fair compromise, ensuring that gay and straight couples are treated equally while reserving marriage for heterosexual couples.

“Civil unions, OK, that’s law. But when you want to redefine marriage, that’s crossing the line,” Pettyjohn said in a telephone interview. “There is no further benefit that same-sex marriage would give to couples than what they have with civil unions.”

Some 30 states have passed constitutional amendments banning same-sex marriage, while nine states and the District of Columbia allow same-sex marriage: Connecticut, Iowa, Maine, Maryland, Massachusetts, New Hampshire, New York, Vermont and Washington.

Same-sex marriage bills are also under consideration in Minnesota, Rhode Island and Illinois.

The U.S. Supreme Court is considering a legal challenge to a 1996 law that restricts federal recognition of marriage to heterosexual couples.